In an attempt to expand the knowledge of the diversity of algal taxa that are capable of successful recovery after freezing to and thawing from -196°C, 365 algal strains representing 13 algal classes were studied using various cryoprotectants at several concentrations. A cryopreservation protocol involving culturing the algae under low light (17-22 μE m⁻² s⁻¹) on semisolid (I % agar) media, controlled cooling at 1°C min⁻¹, rapid thawing, and the return of cultures to agar media was developed. This protocol produced successful recovery of >77% (283) of the algal strains tested. Of the 283 successfully cryopreserved strains comprising 240 species (68 genera), >220 species (34 genera) were cryopreserved for the first time. In addition, preliminary data suggest that some relationships exist among proposed systematic evolutionary lines, environmental preferences, cryoprotectants, and the organism's cryopreservability. / Master of Science